High resolution microscopy is used in research and development, quality assurance and production in diverse fields such as material science, life science, the semiconductor industry and the food industry.
Optical microscopy dating back to the seventeenth century, has reached its brick wall, defined by the wavelength of deep Ultra Violet photons, giving a finest resolution of about 80 nm. The popularity of optical microscopy stems from its relative low price, ease of use and the variety of imaging environment all translated to availability.
Scanning electron microscopy provides a much finer resolution (even few nanometers) but in order to achieve that high resolution the inspected object should be placed in a vacuum environment.
U.S. Pat. No. 6,992,300 of Moses titled “Device and method for the examination of samples in a non-vacuum environment using a scanning electron microscope” describes a chamber that includes an ultra thin member that can withstand a vacuum and is transparent to electrons. The thickness of the membrane is arguably few hundred Angstrom.
Due to mechanical constraints, using an ultra thin membrane implies small supporting aperture. The small size of the ultra thin membrane dramatically reduces the throughput of the scanning electron microscope and renders such a scanning electron microscope impractical.
There is a growing need to provide fast and accurate scanning electron microscopes.